The invention relates to a feeding device particularly for powdered materials into a device processing the same, in particular an extruder, comprising a housing having a receiving region for receiving the materials, which has at least one flexible wall at the side, which is movable by means of at least one moving mechanical element acting on the said wall.
Such a feeding device, frequently also known as a side-loading apparatus, is used in particular in the area of processing granular or powdered materials for the purpose of feeding the respective material in a metered manner to a downstream processing device, conventionally a single- or multiple-screw extruder. The feeding device to this end has a housing, frequently in the form of a hopper or trough into which the material is introduced. The receiving region opens above a conveyor device, conventionally a feed screw or a double screw, via which the material is conveyed longitudinally and is fed in a metered manner to the extruder.
Particularly in the feeding of powdered materials it can arise that the powdered material sticks to the walls of the receiving region and thus continuously reduces the outlet cross-section of the receiving region to the conveyor screws because this region becomes blocked. This results in less material passing into the conveyor screw region, so that consequently less material can be metered in. In order to counteract this it is known to provide the receiving region with at least one flexible wall at the side and to allocate to this wall a mechanical element acting on its exterior, via which element the wall is intermittently moved, i.e. deformed, so that material adhering to it falls off due to the wall's deformation, A mechanical element of this type known in the prior art is formed as a paddle, i.e. a flat plate-like component, which is pivotably mounted about a horizontal axis extending parallel to the wall and which can be pivoted via a corresponding drive. During this pivoting motion it is moved against the flexible wall, presses the wall slightly inward, and deforms the same so that any material clinging thereto falls off. Although in this way any adhesion of material can be to some extent prevented, the mechanical complexity is considerable. Furthermore, as this involves rather slow and harmonically progressing wall deformation due to the relatively slowly effected pivoting motion, substantial detachment of the material cannot always be ensured.